1. Field of the Invention
The present invention relates to digital control of theatre devices, and more particularly to establishing a hierarchy among theatre devices normally remotely controlled by a unidirectional continuous data stream from a central controller and to using a hierarchy, however established, for various purposes such as service and setup, including channel assignment.
2. Description of Related Art
Theatre devices responding to instructions from a remotely located controller are often used for many types of theatre events such as, for example, Broadway shows, television programs, rock concerts, theme parks, the architectural lighting of restaurants and buildings, and other dramatic and entertainment purposes. Theatre devices include multi-parameter lights, haze machines, lighting dimmers, strobes, fans, searchlights, and the like. Typically, theatre devices are wired together with a communications system so that the devices may be operated remotely from a central controller. Some of the theatre effects that can be remotely control including pan, tilt, color, focus, pattern, dimmer, strobe, wind and so forth.
Prior to the advent of relatively small commercial digital controllers, remote control of light fixtures from a central controller was done with either a high voltage or low voltage current; see, e.g., U.S. Pat. No. 3,706,914, issued Dec. 19, 1972 to Van Buren, and U.S. Pat. No. 3,898,643, issued Aug. 5, 1975 to Ettlinger. With the widespread use of digital computers, digital serial communications has been adopted as a way to achieve remote control; see , e.g., U.S. Pat. No. 4,095,139, issued Jun. 13, 1978 to Symonds et al., and U.S. Pat. No. 4,697,227, issued Sep. 29, 1987 to Callahan.
Proprietary protocol schemes for serial communications with theatre devices developed, which left the user desiring to control theatre devices from different manufacturers with the necessity of having to use an array of different equipment using different protocols designed by the respective manufacturers. In response to this situation, the United States Institute of Theatre Technology (xe2x80x9cUSITTxe2x80x9d) in 1986 adopted a standard digital communications system protocol for theatre devices known as DMX512. While the DMX512 protocol has been updated several times since its adoption, the basic communications protocol remains the same. Basically, the DMX512 protocol requires a continuous stream of data at 250 Kbaud which is communicated one-way from the central controller to the theatre devices. Typically, the theater devices use an Electronics Industry Association (xe2x80x9cEIAxe2x80x9d) standard for multi-point communications know as RS-485.
FIG. 1 shows an illustrative theatre system based on the USITT DMX512 protocol. AC power is provided to a central controller 51, multi-parameter lights 21, 22, 23 and 24, dimmers 31, 32, 33, and fan 41 over standard building electrical wiring 1. A communications cable segment 11 is run from the central controller 51 to a first theatre device in the system, illustratively the fan 41, and additional communication cable segments 12, 13, 14, 15, 16, 17, and 18 sequentially connect the dimmer 33, dimmer 32, dimmer 31, multi-parameter light 21, multi-parameter light 22, multi-parameter light 23, and multi-parameter light 24. While only eight theatre devices are shown in FIG. 1 for clarity, typical theatre systems may have thirty or more theatre devices. Communications during a theatre event is in a single direction, as shown by arrows adjacent the communications cable segments 11-18.
Theatre systems based on the USITT DMX512 protocol typically operate using unidirectional communications. The present DMX protocol specifies three wires: (1) data plus; (2) data negative; and (3) ground. In accordance with the DMX protocol, receivers always operate as receivers and transmitters always operate as transmitters. The present DMX protocol does specify the addition of two more wires, a data plus and data negative, to achieve bi-directional full duplex, but the 5-wire full duplex system has not been readily accepted and is not in widespread use.
While bi-directional full duplex communications under the DMX protocol is not in general use, many theatre devices are nonetheless capable of bi-directional communication and use it for updating (uploading) new or improved software from the manufacturer. For example, manufactures of theatre devices such as automated spotlights and complex microprocessor dimmer systems have need from time to time to provide software updates to their theatre devices. As these devices may be installed at remote locations, two way communications between the theatre devices and a host service computer is conducted over the theatre communications system so that the new software can be uploaded to the theatre devices. Since the RS-485 standard allows for two way communication, the bi-directional communications required for uploading is provided by these manufactures using an RS-485 transceiver at the host computer and RS-485 transceivers at the theatre devices. This bi-directional communication (half duplex) between pairs of RS-485 transceivers is not part of the USITT DMX protocol. Since the bi-directional communication used by these manufacturers is only utilized when the device is being serviced or operated with a manufacture""s discrete protocol and not while a controller operating with only the DMX protocol is in use, it does not violate the DMX protocol.
There are various routines used during the upload process. These routines do not have to be DMX512 compatible since during this time they are considered to be in a service mode. This service mode requires that the theatre devices communicate with a host computer or microprocessor. To help facilitate this communication, each theatre device as supplied from the manufacturer typically is equipped with a unique ID number stored within non-volatile memory. This manufacturer supplied unique ID number helps to individually identify the devices to the host computer or microprocessor. In this way, a theatre device may report a failure with the upload process to the host computer or the host computer may find out how may devices are attached to the link to be uploaded. This unique ID number is non-alterable or changeable by the user. During the time when the devices are under the control of a DMX512 compatible controller the devices cannot communicate with each other since the DMX protocol requires a continuous stream of data at 250 Kbaud.
After a theatre system is physically installed, typically it must be set up. A typical setup procedure for a DMX512 compliant unidirectional theatre system such as shown in FIG. 1 requires significant manual intervention and is as follows. A technician connects power and runs data cables 11-18 that carry the DMX512 protocol to the fixtures from the control system 51. Theatre devices that use the DMX512 protocol typically have one or more channels through which various functions thereof are controlled. The channels are set at the device itself, typically by operating address switches or entering the proper commands into the device while watching a display found on the device. FIG. 2 shows an illustrative multi-parameter light 66, which receives power from powerline 68 and is connected into a theatre communications system, typically digital, by cable segments 60 and 62. A display and various controls, generally indicated at 64, are located on the housing of the light 66, and are shown in an enlarged view in FIG. 3. Typical controls include a xe2x80x9cmenuxe2x80x9d button 72, up-count and down-count buttons 76 and 78, and an xe2x80x9centerxe2x80x9d button 74. An illustrative channel address xe2x80x9c024xe2x80x9d appears in display 70. The address xe2x80x9c024xe2x80x9d is set by pressing the xe2x80x9cmenuxe2x80x9d button 72 until a xe2x80x9cchannel assignxe2x80x9d mode notification appears on the display 70, manipulating the counter buttons 76 and 78 until the desired address appears, and finally pressing the xe2x80x9centerxe2x80x9d button 74. Illustrative multi-parameter light devices are described in the product brochure entitled The High End Systems Product Line 1996 and are available from High End Systems, Inc. of Austin, Tex.
Unfortunately, having to manually assign the channels for all of the theatre devices in a theatre system is time consuming and prone to error. Moreover, certain theatre devices such as multi-parameter lights are often required to be placed in hard to reach locations that are accessible only by means of a lift or ladder. In such cases, channel assignments are typically made with the theatre device on the ground, and the theatre device is then lifted to the proper position. When address mistakes are made through human error, the technician must gain physical access to the theatre device by lift or ladder so that he may correct the channel assignment to that required by the operator of the controller.
One embodiment of the invention is a method of establishing a hierarchy among a plurality of bi-directional theatre devices in a theatre system that uses a unidirectional continuous data stream for remote control during theatre events. The method comprises establishing at least one of the bi-directional theatre devices as a master theatre device and a plurality of the bi-directional theatre devices as slave theatre devices; acquiring in the master theatre device identifying information of the slave theatre devices; and determining the hierarchy using the identified information of the slave theatre devices from the acquiring step and identifying information of the master.
Another embodiment of the invention is a method of establishing a hierarchy among a plurality of bi-directional theatre devices in a theatre system that uses a unidirectional continuous data stream for remote control during theatre events, the method comprising furnishing identifying information from each of the bi-directional theatre devices to others of the bi-directional theatre devices; establishing in the bi-directional theatre devices substantially identically ordered lists of the identifying information for the bi-directional theatre devices; and comparing in each of the bi-directional theatre devices the identifying information thereof with the ordered list established therein to determine a position thereof in the list.
Another embodiment of the invention is a method of establishing a hierarchy among a plurality of bi-directional theatre devices in a theatre system that uses a unidirectional continuous data stream for remote control during theatre events, the method comprising arbitrating among the bi-directional theatre devices having no position in the hierarchy to grant control of the communications link to one of the bi-directional theatre devices; assigning to the bi-directional theatre device granted control in the arbitrating step an unassigned position in the hierarchy; and repeating the arbitrating and assigning steps until all of the bi-directional theatre devices have respective positions in the hierarchy.
A further embodiment of the invention is a microprocessor-controlled theatre device having first identifiers and capable of bi-directional communications for use in a theatre system having a controller for furnishing a unidirectional continuous data stream to a group of theatre devices. over a communications link for remote control thereof during theatre events, wherein the group of theatre devices comprises a plurality of other microprocessor-controlled theatre devices having respective second identifiers and capable of a bi-directional communications, comprising means for selecting between master and slave status during bi-directional communication with the other bi-directional theatre devices in the absence of the unidirectional continuous data stream; means for acquiring the second identifiers from the other bi-directional theatre devices over the communications link when having the master status in the absence of the unidirectional continuous data stream; means for broadcasting the first identifier over the communications link when having the slave status in the absence of the unidirectional continuous data stream; and means for determining the hierarchy using the second identifiers acquired in the acquiring step and the first identifier.
Another embodiment of the invention is a microprocessor-controlled theatre device capable of bi-directional communications for use in a theatre system having a controller for furnishing a unidirectional continuous data stream to a group of theatre devices over a communications link for remote control thereof during theatre events, wherein the group of theatre devices comprises a plurality of other microprocessor-controlled theatre devices capable of a bi-directional communications, comprising means for arbitrating for control of the communications link during bi-directional communication with the other bi-directional theatre devices in the absence of the unidirectional continuous data stream; means for maintaining a count of arbitrations lost; and means for assigning a position in a hierarchy based on the count of arbitrations lost when an arbitration is won.
A further embodiment of the invention is a method for a theatre system that uses a unidirectional continuous data stream from a controller to a group of theatre devices over a communications link for remote control thereof during theatre events, wherein the group of theatre devices comprises a plurality of theatre devices capable of bi-directional communications. The method comprises establishing respective positions in a hierarchy for the bi-directional theatre devices in the absence of the continuous data stream; with the unidirectional continuous data stream, instructing at least one of the theatre devices having a position in the hierarchy to respond; in response to the instructing step, operating at least one of the theatre devices in the hierarchy in accordance with the position thereof in the hierarchy and in a manner that is observable to a human observer; and repeating the instructing and operating steps, wherein at least a portion of the hierarchy is perceptible to the human observer.
Another embodiment is a method of establishing an auxiliary mode of operation in a theatre system having a normal mode of operation that uses a unidirectional continuous data stream from a controller to a group of theatre devices over a communications link for remote control thereof during theatre events, wherein the group of theatre devices comprises a plurality of theatre devices capable of bi-directional communications. The method comprises establishing respective positions in a hierarchy among the bi-directional theatre devices in the absence of the continuous data stream; entering an auxiliary mode key code at the controller to place the theatre devices in the hierarchy into the auxiliary mode of operation using the unidirectional continuous data stream; selecting one of the theatre devices in the hierarchy in accordance with the position thereof in the hierarchy from the controller using the unidirectional continuous data stream; operating the theatre device selected in the selecting step in the auxiliary mode from the controller using the unidirectional continuous data stream; and entering a normal key code at the controller to place the theatre system in the normal mode of operation using the unidirectional continuous data stream.
A further embodiment of the invention is a method of channel assignment in a theatre system having a normal mode of operation that uses a unidirectional continuous data stream from a controller to a group of theatre devices over a communications link for remote control thereof during theatre events, wherein the group of theatre devices comprises a plurality of theatre devices capable of a bi-directional communications. The method comprises establishing respective positions in a hierarchy for the bi-directional theatre devices in the absence of the continuous data stream; applying the unidirectional continuous data stream to the theatre devices in the hierarchy from the controller over the communications link; broadcasting a first instruction on the communications link from the controller to place the theatre devices in the hierarchy in a channel assignment mode of operation; broadcasting a second instruction on the communications link from the controller using the unidirectional continuous data stream to evoke a response from at least one of the theatre devices in the hierarchy; operating at least one of the theatre devices in response to the second instruction in accordance with the position thereof in the hierarchy and in a manner that is observable to a human observer; assigning a channel to the theatre device operated in the operating step using the unidirectional continuous data stream; repeating the second instruction broadcasting step, the operating step, and the assigning step at least once; and broadcasting a third instruction on the communications link from the controller using the unidirectional continuous data to place the theatre system in the normal mode of operation.
Another embodiment of the invention is a method for a theatre system having a normal mode of operation that uses a unidirectional continuous digital data stream to communicate from a controller to a group of theatre devices having different channel addresses over a communications link for control thereof during theatre events, and wherein the controller comprises a plurality of channels. The method, which is to access the theatre devices in the group, comprises establishing in the unidirectional continuous digital data stream a predetermined bit pattern reflecting a particular setting of at least one of the controller channels; and evoking a response to the establishing step by each of the theatre devices of the group.